Process for producing cliches for two, three or more color prints, lantern slides, and colored windows and the like



Patented June 23,1931 I Q NIT D STATES. PATENT orrlca LOUIS OSCAR VAN STRBA'BEN, OF IBIGGEKERKE, NETHERLANDS rnoonss non raon-uome dLIcHns ron rwo, THREE on MORE COLOR ram-rs, LANTERN SLIDES, AND COIDBED WINDOWS AND THE No Drawing. Application filed August 29, 1930, Serial No, 478,786, and in the Netherlands a September 6, 1929.--

This invention relates to a process for profirst series of negatives with the employment ducing clichs for two, three or more color of the above mentionedtwo or three or more prints, lantern slides and colored windows color filters, for instance'green, violet andand the like. hen. ciichs are made for orange, Whilst at the same time acorrespondthese purposes, two or three ormore separate ing series of negative imagesare produccdofphotographs have to be taken with the ema strip of paper bearing the primary-colors,

ployment respectively, for example of a for instance blue, yellow and red, theQsaid green, violet or orange light filter, the filters colors being those which are finally used in mg chosen in accordance with the color the printing operations. sensitivity of the light sensitive substance of Preferably each of the colors is provided 60 the photographic plates used. The negatives upon the strip of paper shaded from dark to obtained in this manner have -always"poslight. Y

, sessed considerable inherent faults in respect In addition to the above mentioned negaof the purpose for which they are intended, tives obtained with the color filters for inwhich have to be corrected in order that a stance green, violet and orange 2. second se- 55 natural reproduction of the original object rles of photo raphic negatives are produced may be obtained. For example, certain por- Whilst employing light filters of the corretions of the negatives are not snfiiciently sponding complementary colors for example dense for requirements and have to be inred, yellow and blue. From the latter negatensified. The method hitherto employed tives diapositives are made which have adenfor this correction "consists in retouching the Sity which corresponds to the inherent faults negatives in such. a manner that the faults which are visible on the images of the stri are reduced as much as possible. When the of paper having the primary colors which negatives are used in conjunction with autoappear on the first series of negatives. The type or copper plate printing, the copper or shades of the primary colors on the strip of metal plates obtained by means of these negpaper which is photographed at the same time atives have to be corrected by etching operaas the object to be reproduced are of great tion. 1 assistance when judging the density of the v The described methods of correcting the images 1 th d ap sitiv s.

. negatives and printing plates involves the By placing each of the first mentioned mg 89 expenditure of a large amount of time and atives in contact with the corresponding diaare diificult of, accomplishment and unre positive to formacompound elementin'which liable. The .correction of the negatives must the images coincide exactly, light which passbe effected entirely by hand, which besides es through the negatives with their inherent requiring a large amount of time requires faults, is completely corrected by the said great skill and is even then unreliable as the dia ositives. retouching operation is necessarily effected ompared with the relatively diflicult and without an positive control and results in lengthy operation which is necessary with the density of the retouched portions being known processes, the process according to too great ortoo little. When metal plates this invention has the advantage that the 90 obtained through the medium of the nega operation require much less-time to perform tives are corrected, similar difiiculties arise' as the various photographs may be taken one during the etching operation and in order to directly after the other and the plates or films overcome these difficulties it. is necessary to may be developed simultaneously, after, make frequent trial impressions from the which the diapositives may be made directly 95 plates in the different colors as the etching from the second series of negatives in the operations progress in order to judge the 5 manner above described without any retouch degree of correction eflected by the etching. ing 0 erations.

-The process according'to this invention Alt ough the process according tothis consists in producinginthe known manner'a invention necessitates the use of relatively mo more sensitive plates or films than With known processes and consequently incurs relatively higher costs, these are plentifully compensated by the elimination of the em- 5 ployment of a skilled retouching operator or etcher and the accompanying expenses and further the correction obtained by the process according to this invention is complete and correct which can very seldom 79 if ever be obtained by the known processes.

What 1 claim is 2-- 1. Process for producing clichs for two, three or more color prints, lantern slides, colored windows and the like which com- 15 prises producing a first series of two, three or more photographic negatives of an object with the employment of a corresponding number of difl'erent color filters (for example, green, violet and orange), simultaneously 7-? producing corresponding negative images of primary colors (for example, blue, yellow and red), producing a second series of photographic negatives of the said object with the employment of light filters of the corresponding complementary colors of the said primary colors (for example red, yellow and blue), producing a corresponding series of diapositives from the second series of negatives 01 :1 density which corresponds to the inherent faults of the first series of negatives as disclosed by the images of the three primary colors upon the first series of negatives, so placing each of the first series of negatives with relation to the corresponding 55 diapositives that the images coincide exactly to form a compound element for the purpose set forth.

A process as claimed in claim 1, where-. in the primary colors of which negative images are produced are shaded from dark to light.

In testimony whereof, I afiix my si nature.

LOUIS OSCAR VAN STRAA EN. 

